This invention relates to a rotary switch specially designed for high current applications. One such application is in what may be referred to as a "heat-start switch." This switch is designed to selectively or simultaneously actuate the glow plugs in a diesel engine and the diesel engine starter motor. In one direction of rotation of the switch, the glow plugs are actuated and in the other direction of rotation of the switch, both the glow plugs and the starter-motor are actuated so that the vehicle operator may initially warm the engine cylinders and thereafter, while turning the switch in the other direction of rotation, start the engine.
The glow plugs and the starter motor circuits both carry high current and are therefore very susceptible to arcing across the switch contacts which of course would eventually result in destruction of the contacts. It is therefore very desirable to space the contact members far apart and provide for very rapid contact closure to minimize the effects of this problem.
Another problem in heat start switches presently produced is that they are sensitive to the amount of pressure that the human operator imposes on the switch during operation. This of course is undesirable since it provides a variable set point for the switch and also may cause eventual contact damage. It is therefore desirable to provide a switch in this application which has a predetermined setpoint as a result of the switch design irrespective of the amount of effort the operator employs in actuating the switch.
It is a primary object of the present invention to overcome these problems in rotary switch applications.